Ideally, an FM signal is of constant modulus. Frequency selective multipath fading can cause distortion to a demodulated audio signal and destroy this constant-modulus property. The constant modulus algorithm (CMA) was proposed to minimize multipath effects by restoring the constant modulus feature of the received FM signal. CMA is one kind of blind adaptive algorithm, which is performed using only magnitude information regarding the strength of a processed signal. At weak RF levels, CMA usually can form a very narrow bandwidth low pass filter (LPF) to suppress effects of RF system noise around an FM carrier. However, the effective bandwidth can be so narrow under certain conditions that artificial effects are caused in a resulting FM audio output, which is not desired. Specifically, undesired clipping, dropouts and other distortions can result from use of a CMA algorithm.